The present invention relates to a weapon and in particular to a recoil control mechanism for a weapon. The invention will be described generally in relation to a firearm, however it is to be understood that the invention is applicable to other forms of weapons for firing a projectile. Thus the weapon may, for example, be a large calibre weapon which is supported on a mounting such as a stand or platform instead of a hand held portable weapon such as a firearm.
In this specification the term xe2x80x9cprojectilexe2x80x9d is to be understood as encompassing one piece generally solid projectiles such as bullets, pellets, darts, flechettes, artillery warheads, projectiles as in for example WO 97/04281, mortar shells (eg. 120 mm) or rocket boosted artillary shells, plus multiple piece charges which are fired as one, such as the shot in a shotgun cartridge or a plurality of bullets fired as one.
A problem with all weapons which fire a projectile, particularly those that rely upon detonation of an explosive propellant, is recoil. That is, firing the weapon (for example by detonation of a charge of explosive propellant within the weapon) produces a forward propelling thrust on the projectile and an equal and opposite rearward force, or recoil. Recoil limits the accuracy and portability of weapons. First it produces a force which has the effect of rotating the weapon about the centre of gravity of the weapon and its support (which for a firearm would be the shooter), resulting in vertical climb and lateral drift of the muzzle end of the barrel for succeeding firings. Recoil forces also cause torque, which has the effect of xe2x80x98twistingxe2x80x99 the weapon. The muzzle is thrown off the target in an irregular half circular motion around the longitudinal axis of the barrel. Similar to the effect of muzzle climb, the time of reacquisition of the target is therefore increased for subsequent rounds and accuracy is therefore significantly affected.
During automatic firing recoil can significantly affect the accuracy of the succeeding rounds. Second, the force of recoil must be absorbed by the weapon, or the shooter if the weapon is a firearm, or transmitted to a support mounting and thus to ground for heavier weapons such as artillery pieces. Thus it may cause discomfort and fatigue or even injury to a shooter, or require heavier supporting structures, or complex xe2x80x9csoftxe2x80x9d mounting carriages for mobile artillery weapons. Large masses are sometimes used in firearms to absorb the recoil velocity, however this compromises portability.
Clearly, if the recoil of a weapon could be substantially reduced if not eliminated within the weapon itself, it would reduce the above problems.
There are many known recoil reducing mechanisms, including arrangements which are initiated by the rapidly expanding gases produced by the detonation and burning of an explosive propellant. Generally, however, the known arrangements effectively only reduce the recoil without cancelling or at least substantially eliminating it.
An object of the present invention is to provide an improved recoil control mechanism.
The invention is characterised by the generation of a forward counterforce to the rearward recoil simultaneously with absorption of rearward recoil force momentarily after propulsion of the projectile is initiated.
Accordingly, in a first aspect the invention provides a recoil control mechanism for a weapon for firing a projectile in a forward direction which includes a first mass and a second mass which are driven in substantially opposite directions upon firing, wherein the first mass is driven in the forward direction to counter a rearward recoil of the weapon and the second mass is driven in the rearward direction for absorbing some of the recoil force.
The first mass and the second mass are solid inertial weights.
Preferably the mechanism includes a frame, the first mass and the second mass being associated with the frame for the frame to guide their respective forwards and rearwards movement, and including a force absorbing means which is operative between the second mass and the frame and a force transferring means which is operative between the first mass and the frame.
In a second aspect the invention provides a method of countering recoil of a weapon caused by the firing of a projectile, the method including providing a first mass to be driven forwardly in the same direction as the projectile to counter a rearwards recoil force and providing a second mass to be driven rearwardly against a force absorbing means for substantially simultaneously absorbing some of the rearwards recoil force.
The generation of a forward counterforce simultaneously with absorption of the residual recoil force over the time period of the recoil, allows the achievement of a resultant force-time characteristic which may be reasonably predetermined. For example, for a projectile which is fired by detonation of an explosive propellant, the recoil force of a weapon is reasonably calculable from, knowledge of the amount and type of propellant and the masses etc. that are involved, or it may be empirically determined experimentally, and from this appropriate parameters for the counterforce and recoil absorption sub mechanisms can be calculated (and possibly experimentally adjusted) to give a predetermined resultant force-time characteristic. Thus the invention gives an improved recoil control mechanism. It is envisaged that in some embodiments of the invention, the recoil of the weapon may be at least substantially eliminated if not fully cancelled (that is, the resultant force is substantially zero over the recoil time period). It is also considered that a resultant forward force could be generated.
Preferably the first mass is a barrel and the second mass is a breech block of the weapon and a means is provided associated with the barrel and a frame of the weapon for transferring a forwards force to the frame from the forward motion of the barrel. This means may include a compression spring or pneumatic or hydraulic piston and cylinder arrangement or electromagnetic means which is operative to return the barrel to its firing position.
The barrel and the breech block are also preferably biased towards each other relative to the frame of the weapon. This bias may be provided by a tension spring which is connected between the barrel and the breech block. Thus, as force from the forward momentum of the barrel is being transferred to the frame, the rearwards recoil force imparted to the breech block is being absorbed by the tension spring. Thus the tension spring provides a force absorbing means against which the breech block is driven. The tension spring may also be operative to restrain the breech block in its firing position momentarily upon detonation of the propellant to provide an adequate reaction surface for initiating the forward movement of the projectile and then to return it to its firing position after its rearward movement.
Alternatively the bias of the breech block and the barrel towards each other may be provided by means acting independently between the barrel and the frame and the breech block and the frame. Such means acting between the barrel and the frame may constitute the above described means for transferring a forwards force to the frame from the forward motion of the barrel. The independent means may each comprise a helical spring.
Although the preferred embodiment combines simultaneous xe2x80x9cblow forwardxe2x80x9d of the barrel and xe2x80x9cblow backxe2x80x9d of the breech block to control recoil, as described above, it is to be understood that the invention may be realised in alternative embodiments. For example, it is envisaged that the first mass and the second mass may be additional components and that a gas for driving them apart may be tapped from the barrel or firing chamber. The recoil control mechanism may also be provided as an attachment per se for a weapon. Various of the foregoing or following features for biasing the breech block and barrel and providing gas reaction surfaces may be adapted to the masses of such alternative embodiments.
In the preferred arrangement wherein the first mass is a barrel and the second mass is a breech block of the weapon, a chamber for receiving a cartridge containing the projectile (such as a bullet) and explosive propellant is preferably provided at a loading end of the barrel. The chamber is associated with the barrel and the breech block to provide an interposed gas contact region therebetween for receiving expanding gases from the chamber upon firing of the projectile from the cartridge. Thus, upon firing of the cartridge, expanding gases from the propellant force the projectile from the cartridge and propel it through the barrel, and momentarily after initiation of the projectile""s movement, the expanding gases following the projectile which emerge from the cartridge into the chamber expand into the interposed gas contact region to blow the barrel forward and simultaneously blow the breech block backwards to thereby reduce if not eliminate the recoil of the weapon. The chamber may be provided by the barrel, by the breech block, or the barrel and the breech block in combination, or by a separate chamber member. Preferably the component or components providing the chamber are in a structural relationship such that the interposed gas contact region is defined in part by at least two facing reaction surfaces, with each reaction surface being directly or indirectly associated with one of the barrel or the breech block. Preferably the reaction surfaces are substantially normally orientated relative to the forward and rearward directions to maximise the forces applied thereto in the forward and rearward directions by the gas pressure. The aforesaid structural relationship may be realised by a telescopic arrangement of one component relative to another, as will be described in more detail below.
It is to be understood that the weapon will include a firing mechanism for initiating detonation of the explosive propellant and in the preferred embodiment this may include a firing pin associated with the breech block which is operable via a trigger mechanism carried by the frame, as is known. The weapon may also provide for semi automatic or fully automatic operation utilising the energy stored during the blow back of the breech block, as is also known, in which case a magazine will need to be provided. A suitable firing mechanism and a mechanism for providing semi or fully automatic operation including a magazine for the cartridges will not be described in further detail herein as there are many such known mechanisms from which a person skilled in the art may choose to provide suitable such mechanisms for the weapon.
A weapon incorporating the invention, in its preferred form involving blow forward of the barrel, may include additional features associated with the barrel for increasing the forwards momentum thereof. Such additional features include, for example, the provision of a conical bore for the barrel and/or muzzle breaks for redirecting the gas from the barrel, as are known. The weapon in its preferred form may be a firearm such as a rifle, shotgun, pistol or revolver.
For a better understanding of the invention, the principle thereof for various embodiments, as well as a specific embodiment, which are given by way of non limiting example only, will now be described with reference to the accompanying drawings (which are not to scale).